[Driver] Make linker command generation compatible with LLVM Flang

Upstream commit 1c0958b had changed how the -nostdlib option affects
the linker command generated by the Classic Flang driver. This patch updates
the Classic Flang test case to ensure that the behaviour is consistent with
the LLVM Flang driver.

Author: bryanpkc

clang/test/Driver/flang/classic-flang.f95

@@ -129,10 +129,11 @@
 ! CHECK-NOSTDLIB:      "{{.*}}ld{{(.exe)?}}"
 ! CHECK-NOSTDLIB-SAME: "{{[^"]*}}classic-flang-{{[^ ]*}}.o"
 ! CHECK-NOSTDLIB-NOT:  "-lflangmain"
-! CHECK-NOSTDLIB-SAME: "-lfoo" "-L{{[^ ]*[/\\]+}}basic_linux_tree{{[/\\]+}}usr{{[/\\]+}}lib"
+! CHECK-NOSTDLIB-SAME: "-lfoo"
+! CHECK-NOSTDLIB-NOT:  "-L{{[^ ]*[/\\]+}}basic_linux_tree{{[/\\]+}}usr{{[/\\]+}}lib"
 ! CHECK-NOSTDLIB-NOT:  "-lflang" "-lflangrti" "-lpgmath"
 ! CHECK-NOSTDLIB-NOT:  "-lpthread" "-lrt"
-! CHECK-NOSTDLIB:      "-lm"
+! CHECK-NOSTDLIB-NOT:  "-lm"
 ! CHECK-NOSTDLIB-NOT:  "-lgcc"
 ! CHECK-NOSTDLIB-NOT:  "-lgcc_s"
 ! CHECK-NOSTDLIB-NOT:  "-lc"