The check for "no SOURCE_DATE_EPOCH" wasn't especially interesting, and
I am not aware of a _portable_ way to unset and environment variable in
a lit test. So remove it since it can fail if the build environment has
SOURCE_DATE_EPOCH set globally.
Differential Revision: https://reviews.llvm.org/
D142511
-// RUN: %clang -E %s -### 2>&1 | FileCheck %s -check-prefix=NO_EPOCH
-// NO_EPOCH-NOT: "-source-date-epoch"
-
// RUN: env SOURCE_DATE_EPOCH=123 %clang -E %s -### 2>&1 | FileCheck %s
// CHECK: "-source-date-epoch" "123"