RFR(S): 8213196: [ppc] [s390]: prepare code for gcc7.3.1 warning (int-in-bool-context)

[Schmidt, Lutz]

Dear all, 

may I please request some reviews for this small fix? It adds an additional pair of parentheses to some ad-file code snippets. Without them, operator precedence rules create unintended operand associations when the snippets are embedded into context during adlc processing. As a consequence, gcc fires an “int-in-bool-context” warning.

Bug:    https://bugs.openjdk.java.net/browse/JDK-8213196
Webrev: http://cr.openjdk.java.net/~lucy/webrevs/8213196.00/ 

Thank you!
Lutz