Tests/RunCMake/CommandLine: Match initial cache paths more precisely

Tests/RunCMake/CommandLine/C_basic-stdout.txt

@@ -1 +1 @@
-loading initial cache file ../C_basic_initial-cache.txt
+loading initial cache file \.\./C_basic_initial-cache.txt

Tests/RunCMake/CommandLine/C_basic_fullpath-stdout.txt

@@ -1 +1,2 @@
-loading initial cache file .*/Tests/RunCMake/CommandLine/C_basic_initial-cache.txt
+loading initial cache file [^
+]*/Tests/RunCMake/CommandLine/C_basic_initial-cache.txt

Tests/RunCMake/CommandLine/ExplicitDirs-C_buildsrcdir-stdout.txt

@@ -1,2 +1,2 @@
-loading initial cache file .*initial-cache.txt
-.*
+loading initial cache file [^
+]*initial-cache.txt