Build stability (#715)

* make spotless groovy formatter ignore compilation errors
* move errorprone FieldCanBeFinal to off for performance reasons.
Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

build.gradle

@@ -14,7 +14,7 @@
 import net.ltgt.gradle.errorprone.CheckSeverity
 
 plugins {
-  id 'com.diffplug.gradle.spotless' version '3.13.0'
+  id 'com.diffplug.gradle.spotless' version '3.17.0'
   id 'com.jfrog.bintray' version '1.8.4'
   id 'com.github.ben-manes.versions' version '0.20.0'
   id 'com.github.hierynomus.license' version '0.15.0'
@@ -164,8 +164,9 @@ allprojects {
       check('ImmutableEnumChecker', CheckSeverity.OFF)
       // This is a style check instead of an error-prone pattern.
       check('UnnecessaryParentheses', CheckSeverity.OFF)
+      // Lazy impl causes excess CPU usage O(n) of non-final fiield when it should be O(1).
+      check('FieldCanBeFinal', CheckSeverity.OFF)
 
-      check('FieldCanBeFinal', CheckSeverity.WARN)
       check('InsecureCryptoUsage', CheckSeverity.WARN)
       check('WildcardImport', CheckSeverity.WARN)
     }

gradle/formatter.properties

@@ -49,3 +49,6 @@ org.eclipse.jdt.core.formatter.brace_position_for_enum_constant=end_of_line
 org.eclipse.jdt.core.formatter.brace_position_for_type_declaration=end_of_line
 
 org.eclipse.jdt.core.formatter.insert_new_line_at_end_of_file_if_missing=insert
+
+# Formatter can be buggy in CI
+ignoreFormatterProblems=true