Add -verrors=num switch to control error limit
Add -verrors=0 for fail_compilation tests by default
Remove -verrors swithc from the help messages

Save the lines of help message so it's not very useful for the compiler users.
Merge pull request #4184 from 9rnsr/sw_verrors

Add a new compiler switch -verrors=num to control error report limit
fix Issue 13807 - inout(T)[] no longer matches string[]
add coverage tests for lexer.c
Merge pull request #4190 from 9rnsr/fix13807

[REG2.067a] Issue 13807 - inout(T)[] no longer matches string[]
Merge pull request #4191 from WalterBright/linkercov

add coverage tests for lexer.c