[not][test] Fix disable-symbolization.test when 'printenv' is not ava…

…ilable

On Windows, 'env' or 'printenv' may not exist.

Also switch back to 'env' which is specified by POSIX.1-2017. 'printenv' is not
standard (I picked it because 'printenv' exists on GnuWin32 but 'env' does not).

Reviewed By: zequanwu

Differential Revision: https://reviews.llvm.org/D86496

llvm/test/tools/not/disable-symbolization.test

@@ -1,5 +1,6 @@
-# RUN: not --crash printenv > %t || true
-# RUN: FileCheck %s < %t
+## 'env' may not exist on Windows. %t will be empty.
+# RUN: not --crash env > %t || true
+# RUN: cmp -s %t /dev/null || FileCheck %s < %t
 
 # CHECK-DAG: LLVM_DISABLE_CRASH_REPORT=1
 # CHECK-DAG: LLVM_DISABLE_SYMBOLIZATION=1