Bug 1692945 - Remove unused [YN]ASM variables. r=firefox-build-system-reviewers,andi,dmajor

None of HAVE_NASM, HAVE_YASM, NASM_MAJOR_VERSION and NASM_MINOR_VERSION are
used. Also, the YASM variable is not necessary for old-configure anymore.

Differential Revision: https://phabricator.services.mozilla.com/D105269

build/moz.configure/toolchain.configure

@@ -1988,20 +1988,6 @@ def nasm_version(nasm):
     return Version(version)
 
 
-@depends_if(nasm_version)
-def nasm_major_version(nasm_version):
-    return str(nasm_version.major)
-
-
-@depends_if(nasm_version)
-def nasm_minor_version(nasm_version):
-    return str(nasm_version.minor)
-
-
-set_config("NASM_MAJOR_VERSION", nasm_major_version)
-set_config("NASM_MINOR_VERSION", nasm_minor_version)
-
-
 @depends(nasm, target)
 def nasm_asflags(nasm, target):
     if nasm:
@@ -2024,25 +2010,6 @@ def nasm_asflags(nasm, target):
 set_config("NASM_ASFLAGS", nasm_asflags)
 
 
-@depends(nasm_asflags)
-def have_nasm(value):
-    if value:
-        return True
-
-
-@depends(yasm_asflags)
-def have_yasm(yasm_asflags):
-    if yasm_asflags:
-        return True
-
-
-set_config("HAVE_NASM", have_nasm)
-
-set_config("HAVE_YASM", have_yasm)
-# Until the YASM variable is not necessary in old-configure.
-add_old_configure_assignment("YASM", have_yasm)
-
-
 # Code Coverage
 # ==============================================================