Bug 1450969 - fix paths for MINIDUMP_STACKWALK for Windows build tasks; r=RyanVM

If you happen to be unfortunate enough to be testing changes that crash
xpcshell during the xpcshell self-tests, you'll be presented with error
messages like:

PROCESS-CRASH | test_child_assertions.js | application crashed [unknown top frame]
Crash dump filename: c:\users\task_1522676338\appdata\local\temp\xpc-other-mtot6h\cfaea928-e995-4430-baf9-0066c6b91be9.dmp
MINIDUMP_STACKWALK binary not found: z:\build\build\tools\breakpad\win64\minidump_stackwalk.exe

and then be told that, essentially, "your test failed because it
failed", which is unhelpful for figuring out what went wrong.

Apparently we had MINIDUMP_STACKWALK set at one point, and then it got
moved.  Let's fix this situation by a) downloading minidump_stackwalk
out of tooltool (our test harnesses do this already); and b) pointing
MINIDUMP_STACKWALK at the correct location.  With these changes, we can
once again get crash stacks if xpcshell (and probably a few other
things) fail their self tests.

browser/config/tooltool-manifests/win32/releng.manifest

@@ -21,5 +21,12 @@
     "unpack": true,
     "digest": "196ac6a567c85559957dfe511c3d8654d23c94d5603259e19ccafe9d71e0e4ccee63ccc9a778f2699654b786cda54266108b7d4db543d01bb0b42545b4e6ec75",
     "size": 297118
+  },
+  {
+    "size": 1516544,
+    "visibility": "public",
+    "digest": "cf84f9592059f1e0756370f44e0ad289b71569c235d2ec8c5958695cc57352d3b99b584fd119e73fc9593d1c4cca414985e71f567f777162471b6040ebc59d13",
+    "algorithm": "sha512",
+    "filename": "win32-minidump_stackwalk.exe"
   }
 ]

browser/config/tooltool-manifests/win64/releng.manifest

@@ -21,5 +21,12 @@
     "unpack": true,
     "digest": "196ac6a567c85559957dfe511c3d8654d23c94d5603259e19ccafe9d71e0e4ccee63ccc9a778f2699654b786cda54266108b7d4db543d01bb0b42545b4e6ec75",
     "size": 297118
+  },
+  {
+    "size": 1516544,
+    "visibility": "public",
+    "digest": "cf84f9592059f1e0756370f44e0ad289b71569c235d2ec8c5958695cc57352d3b99b584fd119e73fc9593d1c4cca414985e71f567f777162471b6040ebc59d13",
+    "algorithm": "sha512",
+    "filename": "win32-minidump_stackwalk.exe"
   }
 ]

testing/mozharness/configs/builds/taskcluster_base_win32.py

@@ -7,7 +7,7 @@ config = {
         'PDBSTR_PATH': 'C:/Program Files (x86)/Windows Kits/10/Debuggers/x86/srcsrv/pdbstr.exe',
     },
     "check_test_env": {
-        'MINIDUMP_STACKWALK': '%(abs_tools_dir)s\\breakpad\\win32\\minidump_stackwalk.exe',
+        'MINIDUMP_STACKWALK': '%(abs_src_dir)s\\win32-minidump_stackwalk.exe',
         'MINIDUMP_SAVE_PATH': os.path.join(os.getcwd(), 'public', 'build'),
     },
     'mozconfig_platform': 'win32',

testing/mozharness/configs/builds/taskcluster_base_win64.py

@@ -7,7 +7,7 @@ config = {
         'PDBSTR_PATH': 'C:/Program Files (x86)/Windows Kits/10/Debuggers/x64/srcsrv/pdbstr.exe',
     },
     "check_test_env": {
-        'MINIDUMP_STACKWALK': '%(abs_tools_dir)s\\breakpad\\win64\\minidump_stackwalk.exe',
+        'MINIDUMP_STACKWALK': '%(abs_src_dir)s\\win32-minidump_stackwalk.exe',
         'MINIDUMP_SAVE_PATH': os.path.join(os.getcwd(), 'public', 'build'),
     },
     'mozconfig_platform': 'win64',