[test] do not parse ls output for file size; NFCI

Parsing `ls -l` output to obtain the size of a file is unreliable; the
exact output format is not specified, and some user or group names may
contain multiple words, causing `cut -f5 -d' '` to extract an incorrect
value. `wc -c`, on the other hand, is portable, and there are precendents
of its use in test cases.

llvm/test/tools/llvm-profdata/show-prof-size.test

@@ -1,5 +1,5 @@
 ; RUN: llvm-profdata merge -sample -extbinary -prof-sym-list=%S/Inputs/profile-symbol-list-1.text %S/Inputs/sample-profile.proftext -o %t.1.output
-; RUN: ls -l %t.1.output |tr -s ' ' |cut -f5 -d ' ' > %t.txt
+; RUN: wc -c < %t.1.output > %t.txt
 ; RUN: llvm-profdata show -sample -show-sec-info-only %t.1.output >> %t.txt
 ; RUN: FileCheck %s --input-file=%t.txt
 ; Check llvm-profdata shows the correct file size.

llvm/test/tools/yaml2obj/ELF/custom-null-section.yaml

@@ -71,8 +71,8 @@ Sections:
 ## of the first SHT_NULL section.
 
 # RUN: yaml2obj --docnum=4 %s -o %t4
-# RUN: ls -l %t3 | tr -s ' ' | cut -d ' ' -f 5 > %t.txt
-# RUN: ls -l %t4 | tr -s ' ' | cut -d ' ' -f 5 >> %t.txt
+# RUN: wc -c < %t3 > %t.txt
+# RUN: wc -c < %t4 >> %t.txt
 # RUN: FileCheck %s --input-file=%t.txt --check-prefix=SIZE
 
 # SIZE: [[FILESIZE:.*]]