Bug 1227248 - Part 3: Make GeneratedTest{Certificate,Key} no-op when --disable-compile-environment. r=gps

This implements glandium's suggestion from
https://bugzilla.mozilla.org/show_bug.cgi?id=1227248#c5: since it's
not easy to run xpcshell tests in --disable-compile-environment builds
(and, right now, in artifact builds), let's just skip this work
entirely in those situations.  This saves about 30s of build time on
my machine.

--HG--
extra : commitid : 5IYhHeJlUY3
extra : rebase_source : 3a7b1cf36f45c40f804aad24ba503a5c5863407e
extra : amend_source : 505dcee2221f600962b35a71ee49192b09fdf40c
extra : histedit_source : 96284d832f27f0c734466e63fb6360f49fb6172b

build/test_templates.mozbuild

@@ -6,6 +6,9 @@
 
 @template
 def GeneratedTestCertificate(name):
+    if not CONFIG['COMPILE_ENVIRONMENT']:
+        return
+
     GENERATED_FILES += [name]
     props = GENERATED_FILES[name]
     props.script = '/security/manager/ssl/tests/unit/pycert.py'
@@ -20,6 +23,9 @@ def GeneratedTestCertificate(name):
 
 @template
 def GeneratedTestKey(name):
+    if not CONFIG['COMPILE_ENVIRONMENT']:
+        return
+
     GENERATED_FILES += [name]
     props = GENERATED_FILES[name]
     props.script = '/security/manager/ssl/tests/unit/pykey.py'