[fuzzing] allow fuzz.sh to be called from any directory

fuzzing/echidna.yaml

@@ -2,5 +2,4 @@
 
 testMode: "assertion"       # check that solidity asserts are never triggered
 multi-abi: true             # allow calls to e.g. TestToken in test scenarios
-corpusDir: "fuzzing/corpus" # collect coverage maximizing corpus in this dir
 format: "text"              # disable interactive ui

fuzzing/fuzz.sh

@@ -1,20 +1,24 @@
 #!/bin/bash
 set -e
 
+root=$(cd $(dirname "$0")/.. && pwd)
+
 if command -v echidna-test; then
   fuzz () {
-    echidna-test . \
+    echidna-test ${root} \
-      --config fuzzing/echidna.yaml \
+      --config ${root}/fuzzing/echidna.yaml \
+      --corpus-dir ${root}/fuzzing/corpus \
       --contract $1
   }
 else
   fuzz () {
     docker run \
       --rm \
-      -v `pwd`:/src ghcr.io/crytic/echidna/echidna \
+      -v ${root}:/src ghcr.io/crytic/echidna/echidna \
       bash -c \
         "cd /src && echidna-test . \
           --config fuzzing/echidna.yaml \
+          --corpus-dir fuzzing/corpus \
           --crytic-args --ignore-compile \
           --contract $1"
   }