Use MALLOC_CONF rather than malloc_conf for tests.

malloc_conf does not reliably work with MSVC, which complains of
"inconsistent dll linkage", i.e. its inability to support the
application overriding malloc_conf when dynamically linking/loading.
Work around this limitation by adding test harness support for per test
shell script sourcing, and converting all tests to use MALLOC_CONF
instead of malloc_conf.

test/integration/extent.c

@@ -1,9 +1,5 @@
 #include "test/jemalloc_test.h"
 
-#ifdef JEMALLOC_FILL
-const char *malloc_conf = "junk:false";
-#endif
-
 #include "test/extent_hooks.h"
 
 static void

test/integration/extent.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+if [ "x${enable_fill}" = "x1" ] ; then
+  export MALLOC_CONF="junk:false"
+fi

test/integration/mallocx.c

@@ -1,9 +1,5 @@
 #include "test/jemalloc_test.h"
 
-#ifdef JEMALLOC_FILL
-const char *malloc_conf = "junk:false";
-#endif
-
 static unsigned
 get_nsizes_impl(const char *cmd) {
 	unsigned ret;

test/integration/mallocx.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+if [ "x${enable_fill}" = "x1" ] ; then
+  export MALLOC_CONF="junk:false"
+fi

test/integration/xallocx.c

@@ -1,9 +1,5 @@
 #include "test/jemalloc_test.h"
 
-#ifdef JEMALLOC_FILL
-const char *malloc_conf = "junk:false";
-#endif
-
 /*
  * Use a separate arena for xallocx() extension/contraction tests so that
  * internal allocation e.g. by heap profiling can't interpose allocations where

test/integration/xallocx.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+if [ "x${enable_fill}" = "x1" ] ; then
+  export MALLOC_CONF="junk:false"
+fi